High-intensity interval runs come in many flavors, but in nearly all of them, the recovery intervals between hard efforts consist of slow jogging or passive rest. But so-called new intervals are an exception. Developed by veteran English running coach Peter Thompson, new intervals substitute traditional recoveries with faster “roll-ons” that challenge the body to recover from hard efforts at a higher metabolic rate. Simply put, whereas in a conventional high-intensity interval session you slow down a lot (or stop completely) between hard efforts, in a new intervals workout you slow down only moderately.

The rationale for this twist on familiar interval formats has to do with the physiology of acute recovery from high-intensity exercise. During intense running, the muscles produce large amounts of lactate, which was once thought to be a fatigue-inducing metabolic waste product but is now known to be a critical energy source. The fittest runners are able to use lactate very efficiently, whereas less fit runners are not, which leads to the build-up of lactate in the bloodstream that is observed in all runners when they approach exhaustion at higher intensities.

Some forms of training are more effective than others in developing what Thompson refers to as the lactate energy system. High-intensity efforts in general are more effective than slow-and-steady runs because they produce the largest amounts of lactate. But it’s actually during the recovery periods between hard efforts that the body processes any backlog of lactate that has been produced. When these recovery periods are very slow or passive, this task is fairly easy, but in a somewhat more intense roll-on recovery it’s more challenging, which is good in the sense that it provides a stronger stimulus for strengthening the lactate energy system.

I wouldn’t go as far as to say that new intervals are better than traditional formats. Each has advantages and disadvantages relative to the other. The main disadvantage of new intervals is that, because the recoveries are run at a faster pace, the hard efforts are necessarily run at a somewhat slower pace, and there is something to be said for running really fast, and for allowing yourself the recovery you need to keep running really fast throughout an entire interval session. The lactate energy system is undeniably important, but it is not the be-all and end-all of running fitness. For this reason, my advice is not to replace traditional intervals with new intervals but rather to add new intervals to your repertoire.

photo: 101 Degrees West

The key to successful execution of new intervals is getting the roll-ons right, and this requires practice. The general idea is to slow down just enough between hard efforts to be able to maintain your target pace from the start to the end of however many hard efforts you’re attempting. In other words, roll-on recoveries done by feel, and it takes practice to develop this sense.

As with traditional intervals, new intervals come in limitless varieties and can be formatted to fit the needs of beginners, elites, milers, marathoners, and everyone in between.

The Workout

This particular “new intervals” workout targets 5K race pace, which is something you should do at some point in your training regardless of the race distance you’re actually preparing for. If you are indeed training for a 5K, you’ll want to do more of these sessions, make them pretty challenging, and emphasize them later in the training process. If you’re training for a longer event, you’ll want to do fewer of them, make them less challenging than workouts that are more specific to your chosen race distance, and emphasize them a little earlier in the training process, before you phase in your most race-specific workouts.

Start with a standard warm-up: 1-3 miles of easy running plus a few striders (short, relaxed sprints) and perhaps some technique drills.

The interval part of this workout should be done on a track or other flat, measured course conducive to faster running. It consists of 400-meter efforts at your current or estimated 5K race pace, each followed by a 100-meter roll-on that should be run at a still-brisk tempo that is nevertheless slow enough compared to 5K pace that you feel your body recovering (something you’ll perceive primarily through the slowing of your breathing rate).

If you get it right, you’ll probably be able to get through only a handful of intervals before your roll-on pace starts to slacken. Don’t let this happen. Instead, either end the session or jog slowly for a few minutes and then begin a second set of intervals. The fitter you are, the more intervals you’ll be able to get through without cheating on your roll-ons. Your goal is not to keep going until the failure point, however. Rather, you should break off the session and cool down with a mile or two of easy jogging at the point where you feel you’ve done about 90 percent of what you could handle if you had to.

Here are a couple of specific versions of this particular workout, one for runners of average fitness and the other for runners at a high fitness level:

Average Fitness

  • 4 x (400m @ 5K pace/100m roll-on)
  • 5:00 easy jog
  • 4 x (400m @ 5K pace/100m roll-on)

High Fitness

  • 6 x (400m @ 5K pace/100m roll-on)
  • 3:00 easy jog
  • 6 x (400m @ 5K pace/100m roll-on)

For more information on new intervals, including a variety of other specific formats you can try, visit www.newintervaltraining.com.